The present invention relates generally to optical scanners and, more particularly, to a flatbed optical scanner having an inclined platen.
Optical scanners create electronic data representative of a scanned object. Flatbed optical scanners are stationary devices which have a transparent, horizontally disposed, flat plate or platen upon which an object to be scanned, such as a paper document, is placed. The document is scanned by sequentially imaging narrow strip or scan line portions of the document on a linear optical sensor array such as a charge coupled device (CCD). The optical sensor array produces electronic data which is representative of each scan line portion of the document which is imaged thereon. In one type of flat bed scanner the current scan line portion of the document which is imaged on the sensor array is changed or xe2x80x9csweptxe2x80x9d by moving the platen supporting the document relative to the scanner imaging assembly.
In another, more popular, type of flat bed scanner the platen and document remain stationary and at least a portion of an imaging assembly is moved to change the scan line portion which is currently imaged. A flatbed optical scanner of the fixed platen type has a housing enclosing and shielding various optical and mechanical assemblies of the scanner. The scanner platen forms part of the top portion of the housing. A carriage assembly, typically mounted on horizontal rails, is displaced below and parallel to the scanner. Fixed platen flatbed scanners are disclosed in the following patents, each of which is hereby incorporated by reference for all that is disclosed therein: Boyd et al., U.S. Pat. No. 4,926,041; Boyd et al., U.S. Pat. No. 5,336,878; Henry et al., U.S. Pat. No. 5,339,107, Steinle et al., U.S. Pat. No. 5,410,347; and Steinle et al., U.S. Pat. No. 5,646,394.
As the number of peripheral devices which may be connected to personal computers has increased in recent years, the need to reduce the desk space occupied by such peripheral devices has also increased. Reducing the desk space or xe2x80x9cfootprintxe2x80x9d occupied by a flatbed optical scanners has been very difficult. Certain size reductions have been achieved by reducing the size of scanner mechanical/optical assemblies. However the need for a scanner platen as large as the document which is to be scanned has heretofore limited designers ability to shrink flatbed scanner footprints. A similar design concern is scanner height. A person seated at a desk may use a scanner more easily if he/she can view the scanner platen from a position a foot or more above it. An elevated viewing position allows the user to more easily see and change the relative position of the document on the platen to align it with registration marks, etc. Thus, it is generally desirable to reduce scanner height. Design constraints which limit scanner height reduction include the need for a mechanical carriage assembly positioned below the scanner platen and the requirement for drive motors, etc. positioned within the scanner housing.
The invention may comprise an optical scanner with a housing having a top portion, a bottom portion, a front portion and a rear portion. A platen member forms a portion of the housing top portion. The platen member has a flat upper surface defining a platen plane. A scanner base is provided on the housing bottom portion and defines a base plane. The platen plane is inclined relative to the base plane.
The invention may also comprise a method of scanning a document comprising: placing a document in a planar position with a first edge portion of the document below a horizontal plane and an opposite second edge portion above the horizontal plane; and moving a light source below the document.